Lymphangiogenesis is the formation of lymphatic vessels from pre-existing lymphatic vessels. It plays an important role in promoting neoplasm metastasis. It has been found that vascular endothelial growth factor receptor-3 (VEGFR-3) mediates lymphangiogenesis in response to its two ligands, VEGF-C and VEGF-D. Thus, it is desirable to develop novel drugs that inhibit the VEGFR-3/ligand signaling pathway for cancer treatment.